Red mason stains are largely sensitive to the glaze, but not unstable. The thing that effects a red mason stain (and many mason stains) is Tin in the glaze. Some Ferro frits and other low fire fluxes contain tin to some degree so planning your ^6 glaze is essential before investing in sometimes rather expensive mason stains.

If you have any questions about if your glaze has anything with Tin in it ... let me know ... I'll crack open the books and look it up.
Or check Digitalfire ... it's rather good about that.

Personally i've never been one to use mason stains ... too bland since it just makes this solid color with no characteristics. Nice for a liner and the few mason stain glazes I used in the past were for liners on mugs (lime green liner with an oil spot on the outside for example) but general rule, make a base that you can use any mason stain with so just avoid all zinc and tin in the glaze and you will be fine.

Personally i've never been one to use mason stains ... too bland since it just makes this solid color with no characteristics. Nice for a liner and the few mason stain glazes I used in the past were for liners on mugs (lime green liner with an oil spot on the outside for example) but general rule, make a base that you can use any mason stain with so just avoid all zinc and tin in the glaze and you will be fine.

Atom;The reason that I avoid Mason stains is that they are not fine enough for on-glaze brushing. [see gallery]. I use iron ox., cobalt carb andChrome ox. I use a Degrusia inclusion stain for on glaze reds at cone 10. My purple glaze has tin and copper in it. The reds are not affected. I will get you the number of the stain. Not in the studio right now. It's very expensive, but goes far.TJR.

I find Mason stains to be ground finer than metallic oxides like copper and cobalt.
I remember 20 or 30 years ago that wasn't the case. But it seems they are very fine.
When I add 0.02% to a glaze to change the tinge of it and have no spotting, I am happy.

U.S. Pigments list is for the pound price.
Axner's Mason Stains , not the closeout list, are 4 oz or a 1/4 pound. Usually Mason Stains are list by 4 oz. or 1 pound. Some suppliers list both quantities.